A radio link provides a permanently connected data transfer connection between two points. Radio links are mainly used for mobile network backbone connections alongside optical fibre. Typical data transfer rates for digital radio links vary between 500 Mbps and 1 Gbps, but with suitable technology, it is possible to achieve transmission speeds of up to 2–10 Gbit/s.
The maximum length of the radio link span depends on the frequency band used and the transmission rate depends on the channel width. For example, at frequencies below 10 GHz, the length of the link span can be up to 60 km. In the high frequency range of 71–86 GHz, the lengths of the link spans can reach from a few hundred meters to a maximum of kilometres, and transmission speeds of up to 10 Gbit/s.
Use of radio link transmitters requires a licence
The frequency bands and channel widths available for radio links in Finland can be found in the frequency allocation table included in the Traficom Radio Frequency Regulation (Regulation 4). The instructions on how to apply for a radio licence include the most important information on
- channel widths and channel spacing used in different frequency bands
- applicable standards for radio link equipment
- Traficom’s frequency planning criteria
Based on interference analysis, Traficom determines technical conditions of use for the frequency and polarisation of a radio link transmitter to enable the radio link span to be operated without harmful interference. Conditions may also be imposed on antenna use and transmit power to ensure the efficient use of frequencies.
Traficom’s objective is to issue radio licences within 28 days of receiving the application. Traficom also conducts interference analyses with neighbouring countries and, if necessary, coordinates the use of frequencies with the countries concerned. If cross-border frequency coordination is required, the radio licence may not be granted until the spectrum management of the neighbouring country has approved the frequency use.